Volkswagen Repair: Whirring sound, high humidity, pitch changes

Question
Hi,

2000 Golf GL, 2.0 L engine.  120 000 km. 5 speed transmission.  No accidents or repairs done to the car in 5+ years.

A week ago, noticed a whirring sound coming from the front wheels or engine area.  Radio on or off, sound still occurs.

It only seems to occur when accelerating or decelerating in 1st, 2nd or 3rd gear (once I get up to 4th or 5th, cannot hear it, maybe due to pitch being too high).  It begins at about 10 or 20 km/hr.  The pitch changes as speed changes.  Sound is faint when in 3rd gear.

Also, slight delay of the sound when accelerating.  Example, starting at a dead stop, once accelerating in 1st the whirring sound does not begin immediately.  May take one or two seconds.  Same occurs when shifting into 2nd, 1 or 2 seconds before whirring starts.

As soon as clutch in engaged or I am coasting in neutral at various speeds, there is no whirring sound.  Reving the engine while not in gear does not create the sound.

It has been hot here (30 C, high humidity) for the past week.  Not sure if this could be a factor.

There is no griding or clicking noises.  

Shifting seems normal, no clunking, rough shifting or gears popping out.

What part of the transmission or drive train would be causing this?  

Thanks

Answer
Arn, thank you for your question.  The whirring sound is more than likely the pressure plate.  A couple of other things it can be worn bearings (initially resulting in extended wear generally due to play and backlash.).  My best suggestion is to take it to a reputable transmission shop and have them pull the transmission out and check the bearing for wear.  The bearings in the transmission may need replacing.
Hope that helps